JP4943420B2 - Split composite long fiber nonwoven fabric excellent in lint-free property and production method - Google Patents

Description

  The present invention relates to a production method of a split fiber nonwoven fabric excellent in flexibility and lint-free property, which is excellent in splittability and can be produced at low cost, and uses of the split fiber nonwoven fabric obtainable by the production method.

  Nonwoven fabrics made of ultrafine fibers have excellent flexibility and are not only widely used as materials for clothing, disposable diapers, hygiene products, wiping cloths, etc., but because they are nonwoven fabrics, suspended particles in the air (hereinafter, (Referred to as particles), and it has been used in clean rooms and the like. A clean room is a limited space in which contamination control is performed, in which particles in the air are managed to a level below a limited cleanliness level, and electronic products and optics typified by semiconductor integrated circuits and display products. Widely used in the manufacturing process of products. For example, a semiconductor integrated circuit is manufactured by integrating elements such as transistors and capacitors and wirings connecting them on a silicon single crystal substrate. In this case, the constituent elements and wirings are managed on a scale of several hundred nm to several angstroms. For this reason, in the manufacturing process, mixing of submicron-sized particles directly leads to device defects and wiring defects, leading to a decrease in product yield when manufacturing semiconductor integrated circuits. In addition, since the manufacturing apparatus itself is an ultra-precise device manufactured for the purpose of controlling at the scale, not only the product yield is reduced, but the manufacturing apparatus may be damaged.

  Further, when manufacturing a display product, particles may cause defects in the display unit.

  In recent years, semiconductor integrated circuits have been increasingly miniaturized, and in the case of display products, the display portion has been increased in size and density. Under such circumstances, the influence of the mixing of particles into the manufacturing process on the yield reduction of these electronic products tends to be higher. Therefore, there is an increasing demand for reducing particles in the clean room. Wiping cloth is mentioned as a nonwoven fabric conventionally used in a clean room. As a conventionally used wiping cloth, for example, a nonwoven cloth wiping cloth made of cellulose long fibers is known. However, the cellulose long fiber is generated not a little by dropping of the fiber. Further, it is generally known that the wiping performance of the wiping cloth is improved by thinning the fiber, but the dropping of the fiber from the long cellulose fiber becomes more significant as the fiber becomes thinner. For this reason, the wiping cloth itself may become a particle generation source (hereinafter also referred to as dust generation), which is not preferable for use in a clean room in which particles are reduced in the future. Of the substances that can cause such particles, the fallen fibers are generally called lint.

  On the other hand, non-woven fabrics used in clean rooms are not limited to wiping cloths, and include clean clothes and masks. Such non-woven fabrics are also required to improve the feeling of wearing and to make the fibers extremely fine and, of course, not to be a source of particles.

  From such a background, there is a demand for a nonwoven fabric made of ultrafine fibers with less fiber dropping (lint).

  As a method for obtaining an ultrafine fiber nonwoven fabric, a method comprising treating a fabric composed of multicomponent filaments composed of a polymer having different water swellability or a plurality of incompatible polymer components with a high-pressure water stream (Patent Document 1), a thermoplastic resin As a composite of entangled nonwoven fabric (Patent Document 2) using a fiber-forming low-melting polymer having a melting point difference of 30 to 180 ° C. and an incompatible fiber-forming high-melting polymer, or two different types of resins A split type composite fiber having a predetermined fineness by being discharged from a spinneret having a spinning nozzle and being stretched is deposited on a collecting belt to form a nonwoven fabric, and a fineness obtained by applying an extension force is 0.01 to Nonwoven fabrics by various methods such as a 2.0 denier ultrafine fiber nonwoven fabric (Patent Document 3) have been proposed.

  However, split-type composite fibers composed of components whose melting point differences specifically described in Patent Document 1 and Patent Document 2 exceed 30 ° C. may be insufficiently divided. It becomes complicated. Also, lint from non-woven fabrics is not uncommon. Furthermore, since the difference in melting point is large, a temperature difference occurs during molding, and the low molecular weight component of the polymer on the low melting point side is gasified and adheres to the nozzle surface, and yarn breakage occurs due to temperature unevenness in the nozzle. As a result, there is a problem of greatly reducing productivity.

  Further, in Patent Document 2, when the melting point difference between the two polymers is less than 30 ° C., the high melting point polymer adversely affects the low melting point polymer in the point thermocompression bonding step after forming the web. It is described as being unfavorable because the web tends to shrink and the web tends to shrink, resulting in poor dimensional stability, or the adhesive temperature range at the time of thermocompression bonding becomes narrow and temperature control becomes difficult. No specific example using a polymer having a melting point difference of less than 30 ° C. is described.

Patent Document 3 discloses a split fiber non-woven fabric that is split by gear drawing as in the examples. For example, it is more improved for applications such as clothing or wiping cloth used in a clean room. The demand for non-woven fabrics is high.
Japanese Patent Publication No. 2-14458 Japanese Patent Publication No. 7-49619 International Publication WO2005 / 042824

  The present invention is excellent in flexibility, and is not a source of particles even when used for an application where the surface of a nonwoven fabric is rubbed, such as clothing used in a clean room or a wiping cloth. Various studies have been conducted for the purpose of obtaining a split fiber nonwoven fabric excellent in free property at low cost. As a result, surprisingly, it was found that by using the polyester (A) and the polyolefin (B) having a melting point difference of less than 30 ° C., the splitting property was extremely excellent, and the obtained split fiber nonwoven fabric was lint. We found that it is excellent in freeness.

  That is, in the present invention, the composite spinning nozzle is arranged so that the polyester (A) and the polyolefin (B) having a melting point difference of less than 30 ° C. are in contact with each other. The composite long fiber is spun by discharging from the spinneret, and the spun composite long fiber is cooled by a cooling fluid, and tension is further applied by the fluid or another fluid to narrow the long fiber. A method for producing a split fiber nonwoven fabric, comprising depositing on a collecting belt to form a nonwoven fabric, and splitting the composite long fiber in the nonwoven fabric into a polyester (A) part and a polyolefin (B) part using a high-pressure liquid flow The present invention provides a split fiber nonwoven fabric that can be obtained by the production method and its use.

  The polyester (A) preferably has a higher melting point than the polyolefin (B).

  The split fiber nonwoven fabric of the present invention can be split with a low-energy high-pressure liquid stream (excelling in splitting property) when splitting into a polyester (A) portion and a polyolefin (B) constituting the composite long fiber, and the composite length A split fiber nonwoven fabric obtained by splitting fibers has the characteristics of excellent flexibility, strength, and lint-free properties.

FIG. 1 is a schematic view showing an example of a cross section of a composite long fiber according to the present invention. The five forms (a) to (d) were listed. (E) is an example of the cross-sectional form after a division | segmentation process. In the figure, the white and black portions represent the resins to be combined. FIG. 2 is a schematic view of a gear stretcher used in the comparative example. (A) is a schematic view when a non-woven fabric is processed, (b) is a front view when the non-woven fabric is processed, and (c) shows an enlarged part of the front view. In FIG. 2C, W represents a gear pitch, and H represents meshing.

Polyester (A)
The polyester (A) which is one of the components constituting the composite long fiber of the split fiber nonwoven fabric according to the present invention is various known polyesters that can be melt-spun.

  Among these polyesters (A), a polyester having a melting point (Tme) in the range of 100 to 300 ° C is preferable, and a polyester having a melting point (Tme) in the range of 150 to 300 ° C is more preferable. When the melting point (Tme) is low, it may be difficult to solidify the polyester part when obtaining a composite long fiber by spinning with the polyolefin (B) described later, whereas, when the melting point (Tme) is high, Sufficient cooling cannot be performed at the time of spinning, and fusion of filaments may occur due to cooling delay.

  The melting point (Tme) and crystallization temperature of the polyester (A) according to the present invention were measured by the following known method using a differential scanning calorimeter (DSC).

First, the rate of temperature increase; the rate of temperature increase to about 50 ° C. higher than the temperature giving the extreme value of the melting endothermic curve when the temperature is increased at 10 ° C./min; Hold for a minute.
Subsequently, the temperature was decreased to 30 ° C. at a rate of temperature decrease of 10 ° C./min to obtain a solidification exothermic curve. Again, a melting curve was obtained when the temperature was raised to a predetermined temperature at a rate of temperature rise of 10 ° C./min. According to the method of ASTM D3419, the temperature (Tp) that gives the extreme value of the melting endothermic curve is determined from the melting curve, the endothermic peak of the temperature that gives this extreme value is the melting point (Tme), and the extreme value of the solidification exothermic curve is The temperature given was defined as the crystallization temperature.

  As long as the polyester (A) according to the present invention can be melt-spun, the melt flow rate (MFR, ASTM D-1238) is not particularly limited. For example, when polylactic acid is used, the MFR under a load of 2160 g at 190 ° C. is usually in the range of 1 to 500 g / 10 minutes, preferably 5 to 100 g / 10 minutes, more preferably 10 to 50 g / 10 minutes. When polyethylene terephthalate is used, the intrinsic viscosity [η] obtained by measurement at 20 ° C. in a mixed solvent of phenol: tetrachloroethane = 1: 1 is usually 0.1 to 1.2, preferably 0.3. It is -1.0, More preferably, it exists in the range of 0.5-0.8 dl / g.

  Such polyester (A) includes an aliphatic or alicyclic dicarboxylic acid component (a1), a dicarboxylic acid component (a2) such as an aromatic dicarboxylic acid component (a2) and an aliphatic or alicyclic dihydroxy compound component (b1). A polyester obtained by polymerizing the dihydroxy compound component (b) and, if necessary, a bifunctional aliphatic hydroxycarboxylic acid component (c1), or a bifunctional aliphatic hydroxycarboxylic acid component (c1) or a lactone (c2) Is a polyester obtained by polymerizing

  Specific examples of the polyester (A) include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer, polyethylene naphthalate, and poly 1,4-cyclohexylene dimethylene terephthalate. Examples include aromatic polyesters, poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, polycaprolactone, polyethylene succinate, polybutylene succinate, polylactic acid, polyglycolic acid or aliphatic polyesters such as copolymers thereof. Although not limited to such polyesters.

  In the polyester (A), an antioxidant, a weather resistance stabilizer, a light resistance stabilizer, an antistatic agent, an antifogging agent, an antiblocking agent, a lubricant, a nucleating agent, and a pigment are used as long as the object of the present invention is not impaired. Such additives or other polymers can be blended as necessary.

Aliphatic or alicyclic dicarboxylic acid component (a1)
The aliphatic or alicyclic dicarboxylic acid component (a1), which is one of the components constituting the polyester (A), is not particularly limited, but usually the aliphatic dicarboxylic acid component has 2 to 10 carbon atoms (carboxyl). (Including the carbon of the group), preferably a compound having 4 to 6 carbon atoms, which may be linear or branched. The alicyclic dicarboxylic acid component is usually preferably one having 7 to 10 carbon atoms, particularly 8 carbon atoms.

  The aliphatic or alicyclic dicarboxylic acid component (a1) is a dicarboxylic acid having a larger number of carbon atoms, for example, up to 30 carbon atoms, as long as the main component is a dicarboxylic acid having 2 to 10 carbon atoms. An acid component can be included.

  Specific examples of the aliphatic or alicyclic dicarboxylic acid component (a1) include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, fumaric acid, 2, 2-dimethylglutaric acid, suberic acid, 1,3-cyclopentadicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, itaconic acid, maleic acid and 2,5-norbornanedicarboxylic acid Dicarboxylic acids such as acids, dimethyl esters, diethyl esters, di-n-propyl esters, di-isopropyl esters, di-n-butyl esters, di-isobutyl esters, di-t-butyl esters, di-n of such dicarboxylic acids -Pentyl ester, di-isopentyl ester or di-n-hexyl ester It can be exemplified an ester-forming derivative such as ether.

  These aliphatic or alicyclic dicarboxylic acids or ester-forming derivatives thereof can be used alone or as a mixture of two or more.

Aromatic dicarboxylic acid component (a2)
The aromatic dicarboxylic acid component (a2) which is one of the components constituting the polyester (A) is not particularly limited, but usually a compound having 8 to 12 carbon atoms, particularly having 8 carbon atoms. Compounds.

  Specific examples of the aromatic dicarboxylic acid component (a2) include terephthalic acid, isophthalic acid, 2,6-naphthoic acid, 1,5-naphthoic acid, and ester-forming derivatives thereof. Specific examples of ester-forming derivatives of aromatic dicarboxylic acids include di-C1-C6 alkyl esters of aromatic dicarboxylic acids such as dimethyl ester, diethyl ester, di-n-propyl ester, di-isopropyl ester, di- Examples thereof include n-butyl ester, di-n-butyl ester, di-isobutyl ester, di-t-butyl ester, di-n-pentyl ester, di-isopentyl ester and di-n-hexyl ester. These aromatic dicarboxylic acids or ester-forming derivatives thereof can be used alone or as a mixture of two or more.

Aliphatic or alicyclic dihydroxy compound component (b1)
The aliphatic or alicyclic dihydroxy compound component (b1), which is one of the components constituting the polyester (A), is not particularly limited, but usually 2 to 12 carbons if the aliphatic dihydroxy compound component is used. If it is a branched or linear dihydroxy compound having 4 to 6 carbon atoms, preferably an alicyclic dihydroxy compound component, a cyclic compound having 5 to 10 carbon atoms can be mentioned.

  Specific examples of the aliphatic or alicyclic dihydroxy compound component (b1) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,4-butane. Diol, 1,5-pentanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3 -Propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl-1,6-hexanediol, in particular ethylene glycol, 1,3-propanediol, 1,4 -Butanediol and 2,2-dimethyl-1,3-propanediol (neopentyl glycol); cyclopentanediol, 1,4-cycl Hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol and diethylene glycol, triethylene Examples thereof include polyoxyalkylene glycols such as glycol and polyoxyethylene glycol, polytetrahydrofuran and the like, and particularly include diethylene glycol, triethylene glycol and polyoxyethylene glycol or mixtures thereof or compounds having different numbers of ether units. The aliphatic or cycloaliphatic dihydroxy compound component can also be a mixture of different aliphatic or cycloaliphatic dihydroxy compounds.

Bifunctional aliphatic hydroxycarboxylic acid component (c1)
The bifunctional aliphatic hydroxycarboxylic acid component (c1), which is one of the components constituting the polyester (A), is not particularly limited, but is usually a branched or linear divalent having 1 to 10 carbon atoms. The compound which has an aliphatic group is mentioned.

  Specific examples of the bifunctional aliphatic hydroxycarboxylic acid component (c1) include glycolic acid, L-lactic acid, D-lactic acid, D, L-lactic acid, 2-methyllactic acid, 3-hydroxybutyric acid, 4 -Hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, hydroxypivalic acid, hydroxyisocaproic acid, Bifunctional aliphatic hydroxycarboxylic acid ester-forming derivatives such as hydroxycaproic acid and the like, such as methyl ester, ethyl ester, propyl ester, butyl ester and cyclohexyl ester of bifunctional aliphatic hydroxycarboxylic acid.

Lactones (c2)
Examples of the lactone (c2) that is one of the components constituting the polyester (A) include lactones such as ε-caprolactone, δ-valerolactone, and β-methyl-δ-valerolactone.

Polyolefin (B)
Polyolefin (B), which is one of the components constituting the conjugate fiber of the present invention, is a variety of known polyolefins capable of melt spinning, specifically, for example, α-olefins having 2 to 10 carbon atoms, such as ethylene. , Propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and other homopolymers or copolymers, and α-olefins having 2 to 10 carbon atoms Small amount of polar monomer, for example, vinyl ester such as vinyl acetate, copolymer with (meth) acrylic acid ester such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, styrene, α-methyl Polymers obtained from aromatic vinyl compounds having a vinyl group such as styrene, such as polystyrene, ethylene styrene Polymer is a polymer including such. Of these polyolefins, crystalline polyolefins are preferred.

  Among these polyolefins (B), polyolefins having a melting point (Tmo) in the range of 100 to 350 ° C are preferable, and polyolefins having a melting point (Tmo) in the range of 100 to 300 ° C are more preferable. If the melting point (Tmo) is low, it may be difficult to crystallize the polyolefin part when spinning with the polyester (A) to obtain a composite fiber. On the other hand, if the melting point (Tmo) is high, at the time of spinning. It becomes difficult to perform sufficient cooling, and there is a concern about fusion of composite fibers due to cooling delay.

  The melting point (Tmo) and crystallization temperature of the polyolefin (B) according to the present invention were carried out by the following known method using a differential scanning calorimeter (DSC).

  First, the rate of temperature increase; the rate of temperature increase to about 50 ° C. higher than the temperature giving the extreme value of the melting endothermic curve when the temperature is increased at 10 ° C./min; Hold for a minute. Subsequently, the temperature was decreased to 30 ° C. at a rate of temperature decrease of 10 ° C./min to obtain a solidification exothermic curve. Again, a melting curve was obtained when the temperature was raised to a predetermined temperature at a rate of temperature rise of 10 ° C./min. According to the method of ASTM D3419, the temperature (Tp) giving the extreme value of the melting endothermic curve is obtained from the melting curve, the endothermic peak of the temperature giving the extreme value is taken as the melting point (Tme), and the extreme value of the solidification exothermic curve is given The temperature was taken as the crystallization temperature.

  The polyolefin (B) according to the present invention has a melt flow rate (MFR: ASTM D-1238, a load of 2160 g, as long as it can be melt-spun, but an ethylene polymer, a 1-butene polymer, and an ethylene / acid (derivative). The copolymer is measured at 190 ° C., the propylene polymer is measured at 230 ° C., and the 4-methyl / 1-pentene polymer is measured at 260 ° C.), but it is usually 1 to 1000 g / 10 min, preferably 5 It is -500g / 10min, More preferably, it exists in the range of 10-100g / 10min. The ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyolefin (B) according to the present invention is usually 1.5 to 5.0. From the viewpoint of obtaining a composite fiber having good spinnability and particularly excellent fiber strength, 1.5 to 3.0 is more preferable. In the present invention, good spinnability means that yarn breakage does not occur during discharge from the spinning nozzle and during drawing, and filament fusion does not occur. In the present invention, Mw and Mn can be measured by a known method by GPC (gel permeation chromatography).

  Specific examples of these polyolefins (B) include ethylene homopolymers or one or more of ethylene and propylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene and the like. Known as a copolymer with α-olefin excluding ethylene (ethylene / α-olefin copolymer), such as high-pressure low-density polyethylene, linear low-density polyethylene (so-called LLDPE), medium-density polyethylene, and high-density polyethylene Ethylene-based polymer; homopolymer of propylene (polypropylene) or α-olefin excluding propylene and one or more types of propylene such as ethylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene And propylene / ethylene random copolymer, propylene / ethylene / 1-butene Propylene polymers such as random copolymer, propylene / 1-butene random copolymer (polypropylene random copolymer); poly 1-butene, 1-butene / ethylene random copolymer, 1-butene / propylene random copolymer 1-butene polymers such as polymers; poly-4-methyl / 1-pentene, 4-methyl / 1-pentene / 1-decene random copolymer, 4-methyl / 1-pentene and 12-20 carbon atoms 4-methyl / 1-pentene polymers such as copolymers with one or more α-olefins; ethylene / vinyl acetate copolymer (EVA), ethylene / (meth) acrylic acid copolymer, ethylene / ( (Meth) acrylic acid ester copolymers, ethylene / acid (derivative) copolymers such as ionomers; ethylene / styrene copolymers, isotactic polystyrene Examples thereof include crystalline polystyrenes such as These polyolefins may be used alone or in combination of two or more. In addition, when the said polyolefin is a copolymer, the structural unit which consists of a monomer described initially is a main component of this copolymer.

  For polyolefin (B), antioxidants, weathering stabilizers, light stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, and pigments that are usually used are within the range not impairing the object of the present invention. Such additives or other polymers can be blended as necessary.

Selection of Polyester (A) and Polyolefin (B) In the present invention, the polyester (A) and the polyolefin (B) are each a polyester having a melting point difference of less than 30 ° C., preferably 25 ° C. or less. It is necessary to select (A) and polyolefin (B). Within this range, in view of production stability (spinning stability), the polyester (A) preferably has a higher melting point than the polyolefin (B). By selecting the polyester (A) and the polyolefin (B) in such a temperature range, the obtained composite continuous fiber can be easily divided by a high-pressure liquid flow.

  Further, the smaller the melting point difference is, the more the decomposition of the resin on the low melting point side can be prevented, and the occurrence of troubles during the production of the nonwoven fabric due to the decomposition of the resin can be prevented. Furthermore, it is possible to prevent the nonwoven fabric from causing organic volatile components.

  When the difference in melting point between the polyester (A) and the polyolefin (B) is 30 ° C. or more, the composite long fiber is difficult to split, and the manufacturing process becomes complicated in order to split to the desired fineness. Moreover, the obtained split fiber nonwoven fabric is inferior in lint-free properties. Although the detailed reason is not clear, since the resin on the high melting point side is faster than the resin on the low melting point side to solidify during stretching, the stress concentrates, so the surface on the high melting point side of the obtained composite long fiber Is easily covered with resin on the low melting point side, and as a result, it is difficult to divide the resulting composite long fiber, and the covered part is split unnecessarily, resulting in lint It is estimated to be.

  Further, since it is necessary to mold at a high temperature in order to melt the resin on the high melting point side, the resin on the low melting point side is easily decomposed. For this reason, the decomposed product may adhere to the spinning nozzle and the productivity may decrease.

  Furthermore, not only productivity is lowered, but low molecular weight components generated by decomposition are increased in the nonwoven fabric. Therefore, an organic volatile component may be easily generated from the obtained nonwoven fabric. This organic volatile component is one of the causes of device formation defects particularly in the device formation process when manufacturing a semiconductor integrated circuit. Therefore, it is preferable to suppress the generation of organic volatile components, particularly when used in the vicinity of the process.

  From such a viewpoint, the combination of the polyester (A) and the polyolefin (B) forming the composite long fiber according to the present invention includes poly-L-lactic acid or poly- having a melting point (Tme) in the range of 150 to 180 ° C. Polylactic acid heavy polymers such as D-lactic acid, a copolymer obtained by copolymerizing L-lactic acid and a small amount of D-lactic acid, or a copolymer obtained by copolymerizing D-lactic acid and a small amount of L-lactic acid. Propylene / α such as propylene / ethylene random copolymer, propylene / 1-butene random copolymer, propylene / ethylene / 1-butene random copolymer having a melting point (Tmo) in the range of 135 to 162 ° C. -Propylene polymer such as olefin random copolymer and propylene homopolymer, [melting point of polyester (A) (Tme)-melting point of polyolefin (B) (Tmo)] is to be less than 30 ° C., preferably those appropriately selected. Among these, a combination of a polylactic acid polymer and a propylene / α-olefin random copolymer is most preferable from the viewpoint that the polylactic acid polymer can be easily oriented and crystallized as described later.

  Other polyester (A) and polyolefin (B) combinations include polyethylene terephthalate having a melting point (Tme) of 260 ° C. and 4-methyl / 1-pentene / 1-decene random copolymer having a melting point (Tmo) of 238 ° C. It is most preferable to select a polymer in which the difference in melting point between the polyester (A) and the polyolefin (B) falls within the above range.

Manufacturing method of composite fiber and split fiber nonwoven fabric The composite fiber of the present invention is a composite fiber in which a part made of the polyester (A) and a part made of the polyolefin (B) are in contact with each other, and the polyester (A) This is a composite fiber (also referred to as a split-type composite fiber) having the property of being split with the polyolefin (B).

  The shape (cross section) of the composite fiber is not particularly limited as long as the polyester (A) portion and the polyolefin (B) portion are in contact with each other, but it is divided as shown in FIG. 1 (a) to FIG. 1 (d). It is particularly preferable to have the property of being easily processed.

  In the method for producing a split fiber nonwoven fabric of the present invention, polyester (A) and polyolefin (B) having a melting point difference of less than 30 ° C. are converted from polyester (A) and polyolefin (B) to polyester ( The composite long fiber discharged from the spinneret having the composite spinning nozzle is discharged so that the A) part and the polyolefin (B) part are in contact with each other. Tension is applied by a fluid to make the long fiber thin, and it is deposited on a collecting belt to form a non-woven fabric. Using a high-pressure liquid flow, the composite long fiber in the non-woven fabric is made into a polyester (A) part and a polyolefin (B) part. It is a method characterized by dividing.

  The spunbond method will be described as an example of the method for producing the split fiber nonwoven fabric of the present invention. The polyester (A) and the polyolefin (B) are separately melted by an extruder or the like, and the melts are radially or parallel or parallel as illustrated in FIGS. 1 (a) to 1 (d). A composite long fiber is spun by discharging from a spinneret having a composite spinning nozzle adapted to form a cross-sectional structure.

  At this time, considering the decomposition of the polyester (A) and the polyolefin (B), the melting temperature of these resins is 20 to 40 ° C. higher than the melting point of the higher one among the melting points of the polyester (A) and the polyolefin (B). A high temperature range is preferred.

  The spun composite long fibers are cooled with a cooling fluid such as air, and further, tension is applied to the long fibers with a fluid such as drawn air to reduce the fineness to a predetermined fineness. Deposit. The cooling fluid and the fluid for applying tension to the long fibers to make the fibers thinner may be the same or different. Next, heat embossing is performed as necessary by heat fusion using a heat embossing roll. In the case of heat fusion with a hot embossing roll, the embossing area ratio of the embossing roll is appropriately determined, but is usually preferably 5 to 30%. It is preferable to perform heat embossing by heat fusion using a heat embossing roll, because a nonwoven fabric having better lint-free properties can be obtained.

  In this case, if the polyester (A) is produced so that it is oriented and crystallized by appropriately selecting the molding temperature, spinning speed, and cooling air temperature within a range in which the spinnability is good, a nonwoven fabric with better lint-free properties can be obtained. Therefore, it is preferable. Oriented crystallization as used herein is evaluated by a known crystallinity evaluation method using X-rays.

  The details of the reason why a non-woven fabric with better lint-free properties can be obtained when oriented and crystallized are not clear, but the fiber structure is further strengthened by crystal orientation in the fiber axis direction. It is estimated to be.

  Hereinafter, orientation crystallization of the present invention, that is, crystallinity and orientation characteristics will be described in detail.

  The evaluation of crystallinity and orientation characteristics by X-rays has been introduced in many known literatures for a long time, and is now an evaluation method established as a structural analysis of polymers. For example, edited by the Society of Polymer Science, “Polymer Experimental Laboratory Volume 2”, Kyoritsu Shuppan (1958). Supervised by Nita Isamu, “X-ray crystallography, above”, Maruzen (1959). Kadoto, Kawai, Saito, “Polymer Structure and Properties”, Yukichi Kure, Teruichiro Kubo, Koka, 39, 929 (1939). The evaluation of oriented crystallinity in the present invention is based on the evaluation methods of these known documents. Specifically, for crystallinity, the X-ray total scattering intensity curve of the wide-angle X-ray diffraction profile is used to determine the scattering contribution of the crystalline region and the scattering of the amorphous region. Separated into contributions, the ratio of each area to the total area is evaluated as the crystallinity index value. For example, polylactic acid is known to have crystalline diffraction peaks around 2θ: 16 ° and 18 °, and for example, polyethylene terephthalate has crystalline diffraction peaks around 2θ: 17 °, 18 °, and 26 °. For example, polytrimethylene terephthalate has crystalline diffraction peaks at 2θ: 9 °, 15 °, 17 °, 19 °, 23 °, 25 °, 28 °, and 29 °. In addition, for example, polybutylene terephthalate is known to have crystalline diffraction peaks around 2θ: 9 °, 16 °, 17 °, 20 °, 23 °, 25 °, and 29 °. Evaluation is made by separating the amorphous region from the region to which the crystalline diffraction peak contributes as a crystalline region.

  Regarding the orientation, in the azimuth distribution curve (X-ray interference diagram) obtained by measuring the azimuth distribution strength of the crystal plane peak in the crystallinity evaluation, the fiber is calculated from the half-value width (α) of the peak according to the following formula. The degree of orientation in the axial direction (generally, the degree of c-axis orientation) is calculated and evaluated.

Orientation degree (F) = (180 ° −α) / 180 ° (α is the peak half width in the azimuth distribution curve)
Regarding the crystallinity of the composite fiber composed of the polyester (A) and the polyolefin (B), a crystal peak may be observed on the polyester side, but the crystallinity index value obtained by X-ray diffraction is usually 5 or more, preferably 10 More preferably, it is 20 or more. The degree of orientation is usually 0.8 or more, preferably 0.85 or more, more preferably 0.9 or more.

Method for Producing Split Fiber Nonwoven Fabric The split fiber nonwoven fabric of the present invention can be manufactured by applying stress to the nonwoven fabric composed of the composite fibers by a high-pressure liquid flow. In this step, after the nonwoven fabric is obtained by the known melt spinning production method, the treatment with the high-pressure liquid flow may be continuously performed.

  In the case of applying a high-pressure water flow to a nonwoven fabric composed of composite fibers, specifically, for example, in order to promote entanglement and the like in order to promote the entanglement and the like before dividing the composite fibers by the high-pressure liquid flow and applying the entanglement, It is preferred to replace the air present between them with water. Specifically, water may be applied to the web.

A high-pressure liquid flow can be obtained by injecting the liquid through a nozzle hole and increasing the pressure with a high-pressure pump. As a nozzle hole, a hole diameter is 0.05-1.0 mm normally, More preferably, it exists in the range of 0.1-0.5 mm. The pressure of the high-pressure liquid flow is usually 50 to 600 kgf / cm ² , preferably 50 to 250 kgf / cm ² . In addition, water or warm water is applied as the liquid for ease of handling, and pure water having a specific resistance value of 10 MΩ · cm or more, more preferably 15 MΩ · cm or more, is used with a known water quality measuring apparatus.

  The distance between the nozzle hole and the nonwoven fabric is preferably about 1 to 15 cm. When this distance exceeds 15 cm, the energy given to the nonwoven fabric by the liquid decreases, and the effect of splitting and entanglement of the composite fiber tends to decrease. Moreover, when it becomes less than 1 cm, the formation of the nonwoven fabric tends to be disturbed.

  Generally, the nozzle holes of the high-pressure liquid stream are arranged in a row in a direction intersecting with the traveling direction of the nonwoven fabric. In the case of single-sided treatment, in order to obtain uniform division of the composite fiber and tight entanglement bonding, the injection holes are formed in two or more rows, preferably three or more rows. The pressure of the high-pressure liquid stream is preferably low on the front side and high on the rear side in order to make the formation uniform.

  Furthermore, the pattern of the nonwoven fabric according to the present invention can be changed by appropriately selecting the pattern of the screen belt used when processing the high-pressure liquid flow.

  The non-woven fabric that has been subjected to the division treatment with the high-pressure liquid flow is then dried and heat-treated after the excess water is removed by mechanical squeezing into a final product. The heat treatment temperature time can be selected not only to remove moisture but also to allow moderate shrinkage and promotion of crystallization. The heat treatment may be a dry heat treatment or a wet heat treatment.

  Next, calendar processing by a calendar roll may be performed as necessary. Calendering is preferable because surface fluffing can be suppressed and a nonwoven fabric having better lint-free properties can be obtained.

Split fiber nonwoven fabric The split fiber nonwoven fabric of the present invention is a nonwoven fabric obtained by splitting a polyester (A) part and a polyolefin (B) part that form a composite long fiber obtainable by the above-mentioned production method, and the basis weight is usually 3 to 200 g. / M ² , preferably in the range of 10 to 150 g / m ² .

  The fineness of the split fibers forming the split fiber nonwoven fabric of the present invention is usually in the range of 0.001 to 2.0 denier, preferably 0.001 to 1.2 denier.

  The split fiber nonwoven fabric of the present invention is excellent in lint-free property, specifically, the number of dust particles of 25 μm or less in a test based on JIS-B-9923 (tumbling method) described in the examples is usually 5000 or less, Preferably it is the range of 3000 or less.

The nonwoven fabric according to the present invention may be laminated with other nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, or rayon nonwoven fabrics according to the purpose of use. For the purpose of use as a wet wiper, it is preferable because a nonwoven fabric with improved hydrophilic performance can be obtained by laminating with a rayon nonwoven fabric. Moreover, you may laminate | stack with a film or a porous film. For example, a laminate of a spunbond nonwoven fabric having a relatively large fiber diameter and a split-type composite fiber nonwoven fabric is a preferred form for wiping cloth applications in which dust having a large particle diameter and dust having a small particle diameter are simultaneously wiped. As a method of joining the split type composite fiber nonwoven fabric and the nonwoven fabric produced by another production method, the above-described needle punching, water jet, ultrasonic sealing, or the like, the entanglement treatment, or the heat fusion treatment by the heat embossing roll, and the adhesion Known methods such as adhesive bonding
Wiping cloth The wiping cloth of the present invention has the split fiber nonwoven fabric on the wiping surface. By using such a split fiber nonwoven fabric for the wiping surface of the wiping cloth, a wiping cloth with less lint generation and excellent wiping property can be obtained.

Articles for Clean Rooms The nonwoven fabric of the present invention is excellent in lint-free properties and is unlikely to become a particle generation source, and therefore is particularly preferably used as an article (nonwoven fabric) used in a clean room, that is, an article for a clean room. Examples of clean room articles include crane room wiping cloths, clean room clothing, clean room masks, and the like.

  When used for a clean room, it is preferable to perform a cleaning process to remove adhering atmospheric dust and the like. For example, in a clean room of ISO class 5 (FDIS 14644-1, 1997) Washed with water or warm water (conductivity 4-6 microohms / cm) pre-generated by reverse osmosis using an ionic surfactant and used in semiconductor manufacturing processes with a specific resistance of 15 MΩ · cm or more Examples thereof include a step of sufficiently washing with water having the same specifications as so-called ultrapure water, followed by drying and packing in the atmosphere.

  Moreover, the method of incorporating a washing | cleaning process into the manufacturing process of a nonwoven fabric may be used by making the manufacturing environment of a nonwoven fabric into a clean room, and using the ultrapure water used in a semiconductor manufacturing process as the high-pressure water stream at the time of a division | segmentation.

  EXAMPLES Hereinafter, although this invention is shown by an experiment example, this invention is not limited by the following experiment examples. In addition, the measurement of the division ratio of the nonwoven fabric obtained in the experimental example, the evaluation on the fineness, the softness, the tensile strength, the lint-free property, and the analysis of the fiber structure were performed by the following methods.

(1) Dividing ratio The obtained divided fiber nonwoven fabric is embedded in an epoxy resin, and then cut with a microtome to obtain a sample piece. When this is observed with an electron microscope (S-3500N scanning electron microscope manufactured by Hitachi, Ltd.) and the number of segments of the divided fiber cross section observed from the obtained cross-sectional image is 1, the division ratio is 100%. When the observed number of segments in the cross section of the split fibers was two or more, the split ratio was calculated by the following formula. This was observed for 50 fibers, and the average value was taken as the split ratio of the split fiber nonwoven fabric.

Dividing ratio [%] = (total number of segments−number of observed segments of divided fiber cross section) / total number of segments × 100
Here, the total number of segments refers to the total number of segments forming the filament cross section of the split composite fiber. For example, in the case of a split type composite fiber having a filament cross section as shown in FIGS.

  For example, when a split fiber cross section as shown in FIG. 1 (e) is observed in a filament with a total number of segments of 8 as shown in FIG. 1 (a), the number of segments of the observed split fiber cross section is 3, Further, the division ratio is 62.5%.

(2) Fineness The obtained split fiber nonwoven fabric is embedded in an epoxy resin, and then cut with a microtome to obtain a sample piece. Next, the sample was observed with an electron microscope (S-3500N scanning electron microscope manufactured by Hitachi, Ltd.), 30 undivided filaments were selected from the obtained cross-sectional image, and the cross-sectional area was calculated. The fineness of the undivided filament was obtained, and the fineness of the divided fiber was calculated by the following formula using the division ratio.

Fineness of split fibers = unsplit filament fineness / (total number of segments x split ratio / 100)
(3) Flexibility (45 ° cantilever method)
In accordance with JIS L1096 (6.19.1 A method paragraph), a test with a width of 20 mm x 150 mm in a temperature-controlled room at a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% as specified in JIS Z8703 (standard state of the test place) Five pieces are taken in each of the flow direction (MD) and the transverse direction (CD), and the short side of the test piece is placed on a smooth horizontal table with a 45 ° slope, with the short side of the test piece aligned with the scale baseline. Next, the test piece is manually slid gently in the direction of the slope, and when the central point of one end of the test piece comes into contact with the slope, the moving length of the other end is read on the scale. Bending / softening (bending / softening) is indicated by the length (mm) of the test piece moved, measured for each of the five front and back sides, and expressed as an average value in each of the flow direction (MD) and the transverse direction (CD).

  It is judged that the lower the bending resistance is, the more flexible the nonwoven fabric is. In general, when the value of the bending resistance is 50 mm or less in both the flow direction (MD) and the transverse direction (CD), it is determined that the flexibility is good. However, since the required flexibility varies depending on the purpose of use, it is not necessarily limited to this value.

(4) Tensile strength In accordance with JIS L1906 (6.12.1 A method), the flow direction in a temperature-controlled room with a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% as defined in JIS Z8703 (standard condition of test place) Three non-woven fabric test pieces of 25 cm in (MD) and 2.5 cm in the transverse direction (CD) were collected, and a tensile tester (Instron 5564 manufactured by Instron Japan Company Limited) under the conditions of 200 mm between chucks and a pulling speed of 200 mm / min. A tensile test was conducted using a mold, the tensile load was measured for three test pieces, and the average value of the maximum values was taken as the tensile strength.

(5) Lint-free property As a pretreatment for removing adhering atmospheric dust, etc., a non-ionic surfactant is used to clean the nonwoven fabric at 60 ° C. in a clean room of ISO class 5 (FDIS 14644-1, 1997). It is washed by stirring with high-temperature water (15 liters per kg of nonwoven fabric). Hot water is water that has been generated in advance by reverse osmosis treatment and has a conductivity of 4 to 6 microohms / cm. Next, the substrate was sufficiently washed with water having a specific resistance value of 15 MΩ · cm or more (10 liters per kg of nonwoven fabric), dried at 70 ° C. for 40 minutes, and packed.

  After this, in accordance with JIS-B-9923 (tumbling method), a tumbling dust generation tester (CW-HDT-102, manufactured by Akachi Seisakusho) installed in an ISO class 5 clean room (FDIS 14644-1, 1997) Was run dry and it was confirmed that the inside of the testing machine was dust-free. Thereafter, the packed 25 cm × 25 cm test piece was opened, 10 test pieces were put into the drum, and the drum was rotated at 46 rpm. Using a particle counter (manufactured by Met One A2400B Hach Ultra Analytics) for 1 minute at a suction speed of 1 cubic foot / minute, and measuring particles (particles) in the atmosphere inside the tester 30 seconds after the start of operation of the tester did. The measured value was evaluated as the number of particles per cubic foot. This suction operation was continuously performed, and the measurement was made 5 times in total. Of the five measured values, the remaining measured values (for three times) were evaluated except when the total count was the maximum value and the minimum value. In the evaluation method, the number of particles of 25 μm or less was classified for each particle size, and an average value (three times) was obtained. It was judged that the smaller the number of particles (particles), the fewer the particles generated from the nonwoven fabric, and the better the lint-free property.

(6) Analysis of fiber structure [Confirmation of crystal / amorphous]
Using a wide-angle X-ray device (RINT2500, manufactured by Rigaku Corporation, attached device: rotating sample stage, X-ray source: CuKα, output: 50 kV, 300 mA, detector: scintillation counter), an aluminum thin film is placed in front of the sample on the optical system. From a wide-angle X-ray diffraction profile measured while rotating the holder by irradiating the entire sample with X-rays and weighing the sample so that the sample weight is always 0.2 g. The crystallinity of was evaluated.

(A) Confirmation of crystals of propylene homopolymer and propylene / ethylene copolymer part:
2θ: When a broad peak is observed in the vicinity of 15 ° and 22 °, a smectic crystal is formed.
2θ: The case where peaks were observed at all of 14 °, 17 °, 18 °, and 21 ° was defined as α crystal.

(B) Confirmation of polylactic acid polymer part crystals:
2θ: crystalline when peaks are observed around 16 ° and 18 °,
A case where no peak was observed in the region was regarded as amorphous.

(C) Confirmation of polyethylene terephthalate crystal:
2θ: crystalline when peaks are observed around 17 °, 18 ° and 26 °,
A case where no peak was observed in the region was regarded as amorphous.

(Evaluation of orientation)
Using a wide-angle X-ray diffractometer (RINT2550, manufactured by Rigaku Corporation, attached device: fiber sample stage, X-ray source: CuKα, output: 40 kV 370 mA, detector: scintillation counter), the sample is aligned in the fiber axis direction and fixed to the sample holder. The azimuth distribution curve obtained by measuring the azimuth distribution strength of the crystal plane peak [polypropylene polymer: (110)] plane, polylactic acid polymer part: (110) plane and (200) plane) ( In the X-ray interference diagram), the degree of orientation in the fiber axis direction (c-axis orientation degree) was calculated from the following formula from the half width (α) of the peak and evaluated. In the orientation degree calculated | required by the following formula, when the orientation degree calculated | required by the following formula is less than 0.8, it was judged that orientation was very low and made it non-orientated.

Degree of orientation (F) = (180 ° −α) / 180 °
(Α is the peak half-value width in the azimuth distribution curve)
[Evaluation of crystallinity]
Evaluation of the crystallinity of the polylactic acid polymer part was performed as follows. The diffraction profile 2θ = 5 ° and 35 ° is connected by a straight line to be a baseline. Let I be the total intensity of the diffraction profile below the baseline. Next, peaks around 2θ = 16 ° and 18 ° are taken as peaks, the polypropylene polymer smectic crystal peak and the polylactic acid polymer peak valley are connected by tangent lines, the polylactic acid polymer peak is separated, and both peaks are combined. The intensity is I ₀ . The polylactic acid polymer crystallinity index value is obtained from the following formula.

Polylactic acid polymer crystallinity index value = I ₀ / I × 100
When the crystallinity index value was less than 1, it was assumed to be amorphous.

(7) Water retention The obtained split fiber nonwoven fabric is cut into a size of 50 mm × 200 mm to obtain a test piece. This test piece weight W ₀ is measured and immersed in water for 3 seconds. Next, after removing the water adhering while being held in the atmosphere for 30 seconds by dropping, the weight W ₁ of the test piece was measured, and the water absorption was calculated from the following formula. This was repeated three times and the average value was taken as the water absorption rate.
Water retention [%] = (W ₁ −W ₀ ) / W ₀ × 100
Example 1
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. Using an ethylene random copolymer (Mw / Mn = 2.4, melting point (Tmo): 143 ° C., ethylene content: 4 mol%), the molding temperature of poly L lactic acid was 190 ° C. and propylene A split type composite fiber spinning port having a cross-sectional shape as shown in FIG. 1 (a) in which the molding temperature of the ethylene random copolymer is melted at 200 ° C. and the total number of segments is 16. Spinning split-type composite long fibers having a weight ratio of 50/50 between polyester (A) and polyolefin (B) using gold, and cooling the spun split-type composite long fibers with air (25 ° C.) After stretching at a yarn speed of 2500 m / min, it was deposited on a collection belt. Next, a nozzle with a hole diameter of 0.11 mm is used to divide the fibers, the distance from the nozzle to the nonwoven fabric is 10 cm, and water jet processing is performed on the nonwoven fabric front and back surfaces at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Example 2
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), propylene having a load of 2160 g and MFR at 230 ° C. of 60 g / 10 min・ Ethylene random copolymer (Mw / Mn; 2.4, melting point (Tmo); 143 ° C., ethylene content; 4 mol%) was used. -For the split type composite fiber spinning in which the molding temperature of the ethylene random copolymer is melted at 200 ° C and the total number of segments is 16, the cross-sectional shape is as shown in Fig. 1 (a) A split type composite continuous fiber having a weight ratio of 50/50 between polyester (A) and polyolefin (B) is spun using a die, and the spun split type composite continuous fiber is cooled with air (25 ° C.). After stretching at a yarn speed of 1500 m / min, it was deposited on a collecting belt. Next, a nozzle with a hole diameter of 0.11 mm is used to divide the fibers, the distance from the nozzle to the nonwoven fabric is 10 cm, and water jet processing is performed on the nonwoven fabric front and back surfaces at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Reference example 3
Poly (L) lactic acid polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g and a MFR of 190 g at 190 ° C. (trade name: LACEAH-900, L-lactic acid, manufactured by Mitsui Chemicals, Inc.) / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), propylene alone with a load of 2160 g and MFR at 230 ° C. of 60 g / 10 min Using a polymer [Mw / Mn; 2.75, melting point (Tmo); 163 ° C.], the molding temperature of the poly-L-lactic acid polymer is 190 ° C., and the molding temperature of the propylene homopolymer is 200 using separate extruders. The weight ratio of the first resin to the second resin is 50/50 using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spun split type conjugated filaments, the spun the splittable conjugated filaments with cooling by air (25 ° C.), then was stretched at a yarn speed 2500 m / min, it was deposited on a collection belt. Next, a nozzle having a hole diameter of 0.11 mm is used to divide the fiber, the distance from the nozzle to the nonwoven fabric is 10 cm, water jet processing is performed on the nonwoven fabric surface and back surface at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Example 4
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. An ethylene random copolymer (Mw / Mn = 2.4, melting point (Tmo); 143 ° C., ethylene content; 4 mol%) and alkylpolyoxyethylene alcohol (CH ₃ CH ₂ (CH ₂ CH ₂ ) ₁₃ CH ₂ CH _{2 (OCH 2 CH 2) 2.5} OH) 2.5 using a material obtained by adding kneading wt%, respectively separate extruders with poly L 190 ° C. and prop the molding temperature of the lactic acid Polyester (A) using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spinning a split-type composite long fiber having a weight ratio of polyolefin (B) of 50/50, and drawing the spun split-type composite long fiber with air (25 ° C.) while drawing at a yarn speed of 2500 m / min. After that, it was deposited on the collection belt. Next, in order to divide the fiber, a nozzle having a hole diameter of 0.11 mm was used, the distance from the nozzle to the nonwoven fabric was 10 cm, water jet processing was performed on the nonwoven fabric surface and back surface at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Example 5
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. An ethylene random copolymer (Mw / Mn = 2.4, melting point (Tmo); 143 ° C., ethylene content; 4 mol%) and alkylpolyoxyethylene alcohol (CH ₃ CH ₂ (CH ₂ CH ₂ ) ₁₃ CH ₂ CH _{2 (OCH 2 CH 2) 2.5} OH) 2.5 using a material obtained by adding kneading wt%, respectively separate extruders with poly L 190 ° C. and prop the molding temperature of the lactic acid Polyester (A) using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spinning a split-type composite long fiber having a weight ratio of polyolefin (B) of 50/50, and drawing the spun split-type composite long fiber with air (25 ° C.) while drawing at a yarn speed of 2500 m / min. After that, it was deposited on a collection belt to obtain a split-type composite continuous fiber nonwoven fabric having a basis weight of 20 g / m ² . Next, a 10 g / m ² rayon nonwoven fabric prepared with a card machine using a rayon having a length of 1.7 dtex and a fiber length of 40 mm is laminated between split-type composite continuous fiber nonwoven fabrics having a basis weight of 20 g / m ² to obtain fibers. In order to divide the surface, a nozzle with a hole diameter of 0.11 mm is used, the distance from the nozzle to the nonwoven fabric is 10 cm, water jet processing is performed once on the nonwoven fabric surface and back surface at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. And a laminate of a split fiber nonwoven fabric and a rayon nonwoven fabric with a basis weight of 50 g / m ² was produced. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Example 6
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. An ethylene random copolymer (Mw / Mn = 2.4, melting point (Tmo); 143 ° C., ethylene content; 4 mol%) and alkylpolyoxyethylene alcohol (CH ₃ CH ₂ (CH ₂ CH ₂ ) ₁₃ CH ₂ CH _{2 (OCH 2 CH 2) 2.5} OH) 2.5 using a material obtained by adding kneading wt%, respectively separate extruders with poly L 190 ° C. and prop the molding temperature of the lactic acid Polyester (A) using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spinning a split-type composite long fiber having a weight ratio of polyolefin (B) of 50/50, and drawing the spun split-type composite long fiber with air (25 ° C.) while drawing at a yarn speed of 2500 m / min. After that, it was deposited on the collection belt. Subsequently, this was heat-pressed with an embossing roll (embossing area ratio 18%, embossing temperature 120 ° C.). Next, in order to divide the fiber, a nozzle having a hole diameter of 0.11 mm was used, the distance from the nozzle to the nonwoven fabric was 10 cm, water jet processing was performed on the nonwoven fabric surface and back surface at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Example 7
Poly (L) polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g, and an MFR at 190 ° C. of 47 g / 10 min [made by Mitsui Chemicals, trade name: LACEA H-900, L- Lactic acid / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. An ethylene random copolymer (Mw / Mn = 2.4, melting point (Tmo); 143 ° C., ethylene content; 4 mol%) and alkylpolyoxyethylene alcohol (CH ₃ CH ₂ (CH ₂ CH ₂ ) ₁₃ CH ₂ CH _{2 (OCH 2 CH 2) 2.5} OH) 2.5 using a material obtained by adding kneading wt%, respectively separate extruders with poly L 190 ° C. and prop the molding temperature of the lactic acid Polyester (A) using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spinning a split-type composite long fiber having a weight ratio of polyolefin (B) of 50/50, and drawing the spun split-type composite long fiber with air (25 ° C.) while drawing at a yarn speed of 2500 m / min. After that, it was deposited on the collection belt. Next, in order to divide the fiber, a nozzle having a hole diameter of 0.11 mm was used, the distance from the nozzle to the nonwoven fabric was 10 cm, water jet processing was performed on the nonwoven fabric surface and back surface at a water pressure of 60 kgf / cm ² and a line speed of 5 m / min. The split fiber nonwoven fabric having a weight per unit area of 50 g / m ² was prepared by applying once.

  Next, the obtained split fiber nonwoven fabric was subjected to heat and pressure treatment (100 ° C.) with a calender roll. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Comparative Example 1
Polyester (A) with polyethylene terephthalate having an intrinsic viscosity of 0.77 (Mitsui Chemicals, trade name: Mitsui PET, melting point (Tme); 258 ° C.) and polyolefin (B) with a load of 2160 g at 230 ° C. Propylene homopolymer with MFR of 15 g / 10 min [Mw / Mn; 3.0, melting point (Tmo); 163 ° C.], melted in separate extruders, and molding temperature of polyethylene terephthalate in separate extruders Is melted at 310 ° C. and the molding temperature of the propylene homopolymer is 270 ° C., and a polyester (A) using a split type composite fiber spinning die having a cross-sectional shape as shown in FIG. A split-type composite long fiber having a weight ratio of 50/50 to polyolefin (B) was spun, and the spun split-type composite long fiber was spun into air (25 With cooling by), after stretching at a yarn speed 2500 m / min, it was deposited on a collection belt. Next, using a nozzle with a hole diameter of 0.11 mm for fiber separation, the distance from the nozzle to the nonwoven fabric is 10 cm, water jet processing is performed on the nonwoven fabric surface and back surface at a water pressure of 100 kgf / cm ² and a line speed of 5 m / min. This was performed four times, and a split fiber nonwoven fabric having a basis weight of 50 g / m ² was produced. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

Comparative Example 2
Poly (L) lactic acid polymer having a weight average molecular weight Mw of 117,000, a load of 2160 g and a MFR of 190 g at 190 ° C. (trade name: LACEAH-900, L-lactic acid, manufactured by Mitsui Chemicals, Inc.) / D-lactic acid (copolymerization ratio) = 98.5 / 1.5 mol%, melting point (Tme); 165 ° C.] as polyolefin (B), a load of 2160 g, MFR: 60 g / 10 min propylene homopolymer [Mw / Mn; 2.75, melting point (Tmo); 163 ° C.], melted in separate extruders, and the molding temperature of the poly-L-lactic acid polymer was 190 ° C. in each separate extruder, propylene homopolymer Using a split-type composite fiber spinning die having a cross-sectional shape as shown in FIG. Spinning a split-type composite long fiber having a weight ratio of olefin (B) of 50/50, and drawing the spun split-type composite long fiber with air (25 ° C.) and drawing at a yarn speed of 2500 m / min. After that, it was deposited on the collection belt. Next, this was heated and pressurized with an embossing roll (embossing area ratio 18%, embossing temperature 100 ° C.) to prepare a split-type composite fiber nonwoven fabric having a basis weight of 50 g / m ² .

  Next, the obtained non-woven fabric was passed through a gear drawing machine (gear pitch: 5 mm, gear depth: 3.0 mm) shown in FIG. 2 and subjected to a transverse drawing treatment to produce an ultrafine fiber non-woven fabric having a fineness of 0.25 denier. The obtained nonwoven fabric was evaluated by measuring the division ratio, fineness, softness, tensile strength, lint-free property, fiber structure, and water retention. The results are shown in Table 1.

As is clear from Table 1, as the polyester (polylactic acid polymer) and the polyolefin (propylene polymer), the melting point difference is 22 ° C. (Examples 1 and 2) and the melting point difference is 2 ° C. ( Reference Example 3). The composite long fiber nonwoven fabric using the polymer of) can be easily divided into 90% or more by the water jet process, the fineness of the obtained divided fiber is thin, excellent in flexibility, and the divided fiber nonwoven fabric is Lint-free properties (Example 1: Number of particles; 1940 / ft ³ [= 1940 / 0.02832 (number / m ³ )]), Example 2: Number of particles; 2856 / ft ³ [= 2856 / 0.02832 (Pieces / m ³ )], Reference Example 3 : number of particles; 4939 / ft ³ (= 4939 / 0.02832 (pieces / m ³ )]).

On the other hand, split fibers (Comparative Example 2) having a large melting point difference of 101 ° C. between the polyester part and the polyolefin part need to be subjected to water jet processing four times each on the front and back surfaces of the nonwoven fabric (Comparative Example 2). In addition, the fineness of the resulting split fibers is reduced but the flexibility is inferior, and the lint-free property is also inferior (number of particles: 5699 / ft ³ [= 5699 / 0.02832 (number / m ³ )]). It became a thing.

On the other hand, a split fiber nonwoven fabric (Comparative Example 2) obtained by splitting a composite long fiber nonwoven fabric with a gear drawing machine has lint-free properties (Comparative Example 3: number of particles; 24695 particles / ft ³ [= 24695 / 0.02832 ( Piece / m ³ )] ) was extremely inferior.

  The split-type composite fiber nonwoven fabric that can be obtained by the method for manufacturing a split fiber nonwoven fabric of the present invention has flexibility and hardly loses fibers when it is used for applications where the nonwoven fabric surface is rubbed, such as clothing or wiping cloth. For this reason, as articles used in clean rooms when manufacturing electronic products such as semiconductor integrated circuits and display products, optical products, etc., that is, as materials for clean room clothing, masks, wiping cloths, etc. It can be particularly preferably used.

  In addition, because it has high lint-free properties, it can be used for other purposes besides clean room use, such as various wiping cloths, non-woven fabrics for clothing such as surgical gowns, medical gowns and industrial gowns, packaging fabrics, It can also be widely used for surface materials of sanitary materials such as disposable diapers and napkins, bedding such as bed sheets and pillow covers, carpets and base fabrics for artificial leather.

  Other applications include VTR and compact disc cleaning cloth, disc polishing, filter cloth, general consumer materials such as glass, precious metals, high-quality items, window glass, OA equipment, automobile windows, musical instruments, mirrors, etc. Examples include dirt removal, oil film removal, flooring, and toilet cleaners.

Claims (9)

  A polyester (A) composed of a polylactic acid polymer having a melting point difference of less than 30 ° C. and a polyolefin (B) composed of a propylene / α-olefin random copolymer, a polyester (A) part and a polyolefin (B) The composite long fiber is spun by discharging from a spinneret having a composite spinning nozzle so as to be in contact with each other, and the fluid or another fluid is further cooled while the spun composite long fiber is cooled by a cooling fluid. The long fibers are thinned by applying a tension by means of the above, and are deposited on a collecting belt, and then the composite long fibers are divided into a polyester (A) part and a polyolefin (B) using a high-pressure liquid stream. A method for producing a split fiber nonwoven fabric. The method for producing a split fiber nonwoven fabric according to claim 1, wherein the polyolefin (B) is a propylene / α-olefin random copolymer containing an alkyl polyoxyethylene alcohol . The method for producing a split fiber nonwoven fabric according to claim 1 or 2 , wherein the high-pressure liquid stream is a high-pressure water stream. The split fiber nonwoven fabric obtained with the manufacturing method in any one of Claims 1-3 . The split fiber nonwoven fabric according to claim 4, wherein the polyester (A) portion is oriented and crystallized. Based on JIS-B-9923 (tumbling method), the number of particles of 25 μm or less measured using 10 pieces of 25 cm × 25 cm non-woven fabric pieces is 3000 / ft ³ [= 3000 / 0.02832 (pieces / m ³ ). The split fiber nonwoven fabric according to claim 4, wherein: The split fiber nonwoven fabric according to any one of claims 4 to 6 , wherein the fineness of the split fibers is in the range of 0.001 to 2.0 denier. A wiping cloth comprising the split fiber nonwoven fabric according to any one of claims 4 to 7 . The article for clean rooms containing the split fiber nonwoven fabric in any one of Claims 4-7 .

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